To meet a seamless coverage requirement of a communications network, the prior art proposes a heterogeneous network (Hetnet). The Hetnet is a network formed by cells of various sizes and types, such as a macro cell (Macro cell), a micro cell (Micro cell), and a pico cell (Pico Cell). A base station of a macro cell manages multiple cells. A base station of a micro cell or of a pico cell manages only one cell.
In a WCDMA communications network system, a downlink of a WCDMA system has totally 512 scrambling codes (Primary scrambling code, PSC). Each cell is allocated with a PSC used as one of identification parameters of the cell. However, the number of PSCs used by a micro cell in the WCDMA communications system is limited. In this case, for micro cells having overlapping coverage with a macro cell, multiple micro cells share a PSC. Further, when performing measurement on a neighboring cell, a UE is incapable of reading identification parameters other than PSC information of the neighboring cell. To ensure that a user equipment (UE) successfully hands over from a macro cell to a target micro cell having overlapping coverage with the macro cell, after sending a handover message to a gateway managing the target micro cell, an RNC (radio network controller) managing the macro cell manages the gateway of the target micro cell to select the target micro cell by using information such as uniqueness of a timing difference between a micro cell and the macro cell that have the same PSC when only PSC information of the target micro cell and information of a timing difference between the target micro cell and the macro cell can be acquired, so as to hand over the UE.
However, frame timings of base stations of the target micro cell and the macro cell may drift, so a timing difference between the frame timing of the base station (BS) of the target micro cell and the frame timing of the base station of the macro cell may also change, in which case the timing differences between the macro cell and micro cells having the same PSC may be the same. When a target micro cell is determined by using information such as a PSC of the target micro cell and a timing difference between the target micro cell and a macro cell, because information of the timing difference between the micro cell having the same PSC and the macro cell which a UE is in is not unique, a gateway of a micro cell cannot determine the target micro cell, in which case the UE cannot hand over to the target micro cell.